Cone of cold effect replacing frostbolt effect.

[Natla]

This is normal behavior. The CoC is superior slow rebuff than frostbolt, so it will overwrite the former if present

Yes, this was correct on retail.

Why Blizzard doesn't overwrite CoC then ?

Not a direct effect snare.

Please read Stalk's first response. Blizzard should overwrite CoC.

Proof : https://youtu.be/unusjpGt8bY?t=94
You can see that CoC is not applied.

And Blizzard is a direct effect snare. It's just non-targeted, same as CoC.

[stimz]

Nah, shits just broken. I recall snares not stacking with each other, here you can have wing clip, frostbolt, imp bliz, hamstring and crippling on the same target. Obviously the snares don't stack but the end result is allowing horrible frost mages to be a threat.